Many studies have reported aberrations such as amplifications, deletions and translocations of 1q21-q23 in ovarian tumors. These findings increase the scientific interest in analyzing this region using spe­cific gene probes. We investigated the frequency of copy number changes of two specific bacterial ar­tificial chromosomes (BAC) clones in 1q21.3 and 1q23.3 by fluorescent in situ hybridization (FISH) on tissue microarrays consisting of 540 ovarian tu­mors of different malignancies, histology, stage and grade. Such changes in 1q21.3 were established in 9.64% ofmalignant (2.41% amplification), in 8.33% of low malignant potential (LMP) and in 13.13% of benign ovarian tumors. Copy number changes of 1q23.3 were found in 17.78% of malignant (1.48% amplification), in 16.67% of LMP and in 12.64% of benign ovarian tumors. We found a significantly higher gain of 1q23.3 in non epithelial (50%) com­pared to epithelial tumors (14.73%) (p <0.03). The gain of 1q21.3 prevailed in non serous malignant and LMP ovarian tumors in comparison to serous tumors. In non serous tumors, both gains were as­sociated with higher grade. The frequency of gain in 1q23.3 was 2.5-times higher than that in 1q21.3 of ovarian cancers.